1. Field of the Invention
This invention relates to the fields of petroleum seismic exploration, geology, acquisition of seismic data for coal mine resources, and earthquake detection.
2. Related Art
Following the development of the technology of geophysical exploration, seismic prospecting is directed towards higher mountainous regions in which it is more difficult to work and all remote transmission seismic apparatuses of real time transmission by cable/wireless have had more and more difficulty meeting the requirements of practical prospecting.
For example, remote transmission seismic apparatuses using cables entail carrying large bundles of cables to mountain cliffs. This results in the use of a great amount of labor and transporting equipment, is very dangerous, and frequently results in casualties and damage to the equipment. In addition, it is frequently impossible to deploy cables to a designed position as a result of the limitation in length of the cables, so that channels may be emptied or lost.
Although a remote transmission seismic apparatus using wireless transmission is convenient, the system usually loses channels and/or stations in mountainous regions as a result of the blind regions of radio transmission. The workload is increased because the great amount of electric energy consumed by wireless transmission needs heavy power supply equipment. The efficiency of the deployment of wireless remote transmission seismic apparatuses decreases along with the increase of channels deployed because more time is needed for the real time data return transmission. The aforementioned two kinds of seismic apparatuses have had very much difficulty meeting the needs of the field when the work is in mountainous areas with very bad topography.
The applicants have invented remote transmission seismic apparatuses using GPS (Global Positioning System) satellite timing, which has “no central units (main seismometer), no cables, and no radio stations, and is portable, cheap, and intelligent” (the application numbers of those Chinese patents are CN01134726.0 and CN02129603.0) for compensating for the shortage of real time transmitting seismic apparatuses in the fields of system conveying, arrangement of cables for prospecting, data transmission, and communication. The remote transmission seismic apparatuses using GPS satellite timing are especially suitable to seismic prospecting work in complicated because the apparatus has two manners of working, timing data acquisition and continuous data acquisition, so that the working efficiency of seismic data acquisition in those fields is increased and the cost is decreased.
The non-real time transmission seismic data acquisition apparatus uses high accuracy GPS clock signals to synchronize the system clocks of every acquisition unit and remote detonating unit, and works by way of timed and synchronized detonating and recording. In operation, the detonating and recording units all operate according to a flow chart designed for the system without any artificially intervention. If the system operates 12 hours every day and acquires and records data for every minute, the numbers of original record files in every data acquisition unit every day are equal to 12×60, i.e., 720 original record files every day. If the system operates 12 hours every day and acquires and records data for every ten seconds, the numbers of original record files in every data acquisition unit every day are equal to 12×60×6, i.e., 4320 original record files every day. The number of original files in the data acquisition units increase as the number of data acquisition units and the data acquisition time increase (i.e., increase by degrees of geometric series). Therefore, whether or not the present system is capable of being applied in practice, the key points are how to manage and safely retrieve these original record files.